Thursday, August 19, 2010

Keeping the Water Flowing to Your Home from a Well

Private well owners are responsible for maintaining the water supply to their homes as well as monitoring their water quality. Water well pump systems operate on electricity, so in power failures there is no water and no (or limited) septic if your system operates on a pump. (Note also that well pumps operate on 240v and if they should blow a fuse there are two fuses to replace or two circuit breakers to flip. A pump might work poorly on 120 volt if only one fuse or circuit breaker is blown disguising a simple problem. So, always check your fuses or circuit breakers first whenever you have a water supply problem. ) As the winter storms and recent thunder storms and power outages have reminded us, sometimes power can be lost for days. A small portable liquid gas or diesel-powered electricity generators are available that can operate the pump or full-system generators that will run your well, refrigeration, heating, cooling, and other systems in your home, will keep your well operating in an emergency. I have an automatic switch generator connected to liquid propane in ground tank to operate my home in an emergency.

Besides power outages, there are other causes of failure of your water system. A component of the well or pump system might fail or the well itself might develop problems. The most common type of private water well pump is the submersible pump which pushes water to the surface as opposed to jet pumps that pull water. Submersibles are more efficient than jet pumps or the older water rams. The entire pump assembly is submerged below the water level in the well. The main advantages of this type of pump are that it keeps the pump cool and can prevent pump cavitations, which is basically sucking air and reducing the life of your pump. The presence of air or other gases in the actual pump chambers or around the water pump impellers leads to overheating of these parts and mechanical damage to the pump’s moving parts. Cavitations can also cause the pump to have to work longer to meet the water demand which in turn can cause its electric motor to overheat, reducing motor life. Falling water level in a well could cause pump failure so that both your well and the pump end up failing simultaneously. Without testing the well, you might replace the pump only to have the new pump fail over a short period of time.

The most common cause of falling water level is the slowing of the recharge of water to the well. . This can be caused by a falling of the water level due to drought or over pumping of the aquifer or the plugging of holes along the well’s casing and mineral crusts forming on the well screens if the well casing extends to the water table. My well was drilled in siltstone and the casing only extends for the first forty feet of the well. This method prevents clogging of a screen in a firm substratum that contains hard water (which is likely to deposit lime scale on the screen) and is cheaper to drill. However, an unscreened well might allow larger stone particles to be pulled up by the impellers and wrack the pump or damage the impellers. Dealing with natural systems like groundwater and local geology there is no perfect design. The life of a well and its pump is determined by geology, mineral content of the water, operation hours and a number of other factors that can result in a wide variability in well and pump system life from five to twenty-five years.

Calcium carbonate, iron bacteria, silt, clay, and “slime,” a combination of sediment and deposits on well casings and screens, are all common causes of a clogged well. A clogged well can be rehabilitated rather than just drilling a new well. (This may only be cost effective in deep wells or fully screened wells.) Two typical methods are (1) using mild acids to dissolve the incrusting materials so they can be pumped from the well and (2) cleaning the well with a brush that can be attached to a drilling rig and then used in the well. High pressure jetting, hydro fracturing, and well surging are procedures in which water is injected into the well at extreme pressures. Well service companies will often use a combination of these methods to rehabilitate an older well, the additional life gained from these procedures could be decades or months. Slime buildup can also cause persistent coliform bacteria presence. For iron bacteria and slime, a liquid bacteria acid is effective. For clogs with calcium carbonate scale, sulfamic acids are used with inhibitors and modifiers. If the bacteria problem is persistent some of the more aggressive chemicals are muriatic acid and hydroxyacetic acid.

Over time the amount of water a well produces can decrease. Sometimes that is because the water table is dropping. Other times it can be caused by the plugging of holes in the well casing, mineral encrustation of the well screen or the filling of openings in the geologic formation around the well from which water flows as discussed above. The pump performance could also be impaired by a damaged motor or impeller. The solution can not be properly identified until the cause of the problem is identified. A well check-up should be performed regularly and whenever a problem is noticed. This check up should include four components. First, is a flow test to determine system output, along with a check of the water level before and during pumping (if possible). Second is to check pump motor performance (check amp load, grounding, and line voltage), pressure tank and pressure switch contact, and general water appearance. (This will not necessarily identify a pump that is going to fail shortly). Next, is an inspection of well equipment to assure that it is sanitary and meets local code requirements. Third, a test of your water for coliform bacteria and nitrates, and anything else of local concern should be performed. These tests while not exhaustive, should allow you to differentiate between a pump problem, well/water supply problem, and other system problems.

I can not over emphasize the importance of a systematic approach to identifying a problem. Remember, well drillers and service companies while very knowledgeable are in the business of selling and installing equipment their knowledge and veracity will vary. You can get help in understanding a well check up report from the The Master Well Owners project volunteers in your area. This is a federally funded program operating in the mid Atlantic states. The Virginia Master Well Owner Network is a group of trained, dedicated Virginia Cooperative Extension agents and volunteers who have completed training about protecting and maintaining private water systems such as wells, springs and cisterns, and about water conservation, testing and treatment. This network is designed to provide practical information to private water system owners on the proper management of private water wells. One final thought, generally speaking the nearest source of water contamination to your drinking water well is your own (or neighbors) septic system. At a minimum you should inspect the septic tank each year for capacity and leaks, pump out the tank every three years (according to the newest recommendations from the US EPA) rather than the minimally required five years here in Virginia, watch for indications of impairment to your leach/drain field. When a septic tank is not pumped out often enough, sludge (solid material) builds up inside the septic tank, and then flows into the leach field, clogging it beyond repair. Excessive load from toilets and garbage disposal, putting grease, coffee grinds, kitty litter down the drain will shorten the life of and potentially overload the system. Even with proper use and maintenance the system will wear out. Eventually, the soil around the leach field becomes clogged with organic material, forcing sewage upward into the yard (bright green strips of lawn over the leach field) or back into the house (black liquid in the toilets or slow flushing or draining).

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